The inventive concepts relate to three-dimensional (3D) semiconductor devices and, more particularly, to 3D semiconductor devices capable of improving reliability and integration density.
Semiconductor devices have been highly integrated to provide high performance and low costs. The integration density of semiconductor devices may affect the costs of the semiconductor devices, thereby resulting in a demand of a highly integrated semiconductor device. An integration density of a conventional two-dimensional (2D) or planar semiconductor device may be mainly determined by an area where a unit memory cell occupies. Therefore, the integration density of the conventional 2D semiconductor device may be greatly affected by a technique of forming fine patterns. However, since extremely high-priced apparatuses are needed to form fine patterns, the integration density of 2D semiconductor devices continues to increase but is still limited. Thus, three-dimensional (3D) semiconductor devices including three-dimensionally arranged memory cells have been developed.